KR102637476B1 - Paper bag and production method for a paper bag - Google Patents

Abstract

The present invention relates to a paper bag for cement, plaster, granular material, animal feed or the like bulk material, having a bottom and an upper part facing the floor, wherein the bottom and/or upper part intersects or At least one adhesive or bonding agent is provided in the form of a block bottom, folded and glued by sealing the side parts around a side fold line, wherein the adhesive or bonding agent is activated after application for bonding the side parts, said adhesive or The binder is applied continuously from at least one side fold line of the side portion to at least the opposite side fold line.

Description

Paper bag and its manufacturing method {PAPER BAG AND PRODUCTION METHOD FOR A PAPER BAG}

The invention relates in particular to a paper bag for fine-granular bulk materials, such as cement, plaster, granular material, animal feed or the like, having a bottom and an upper part facing the bottom, wherein the bottom and /or the upper part is folded and glued by sealing the side parts around the side fold lines, especially in the form of a cross or block bottom. Another aspect of the invention relates to a specific manufacturing method for such paper bags.

Common paper bags are known, for example, from EP 1 858 769 B1. Typical sizes of 5 kg, 10 kg or 25 kg are particularly popular commercially. They have one or more paper layers formed from paper or paper composites and/or coated paper. Additionally, layers of other materials may exist, and for example, EP 1 858 769 B1 discloses a layer of a plastic film material.

These paper bags are generally made from endless paper webs whose longitudinal edges are glued together to form a tube. To form the bag, the tube is cut into sections of appropriate length, and at the open end of the tube the bottom and top portions are folded and glued to seal the paper bag at the floor and/or ceiling. Typically cross or block bottom folds are chosen, where overall creasing or the like is made to facilitate folding in the area of the fold lines. The folds are usually glued together by an adhesive such as a starch-water mixture. However, for manufacturing reasons, the adhesive used should not be left in the fold area. This limitation is due to the fact that the adhesive in the fold area and in the edge area contaminates the production machine for the production of paper bags, thereby making serial production of paper bags not possible. In particular, when applying corrugation at the fold line, the adhesive application present in these areas can lead to severe contamination of the tools used in the machine for corrugation. In addition, if a starch-glue pattern is applied, it is likely to result in otherwise soiling and gluing of any mechanical device together, and also any minimum distance from the edge or beveled edge of the bottom/top part. Distance must be maintained.

However, once the adhesive is released, non-adhesive areas remain along the fold lines and edges/beveled edges in the bottom and/or top portion of the paper bag. This may also create a channel that provides for the escape of dust-like filling material after the bag is closed.

Additionally sealing the bottom/top part creates a certain compression on the paper, whereby folds and displacements as well as undulations of the paper occur in the area of the adjacent edges of the center of the bottom, which also It is called the bottom center line. Since the starch adhesive is not completely injected and does not reach the fold edges, these reliefs, folds and edges also cannot be completely bonded with the starch adhesive. This causes additional channels to be created next to the channels in the fold line, which increases the amount of peeling material released.

The present invention therefore addresses the object of providing more dust-tight paper bags.

Prior art: EP 1 858 769 B1 (Dy-Pack Verpackungen Gustav Dyckerhoff Gmbh, published on November 28, 2007) Paper sack

The object of the present invention is to provide more dust-shielding paper bags.

The object of the invention is solved by the paper bag according to the feature of claim 1 and the manufacturing method according to the feature of claim 10. The advantageous features of the paper bag and the method for producing the same are the subject of the dependent claims following each independent claim.

The invention proceeds from an ordinary paper bag having the features of the preamble of claim 1. According to the invention, at least one adhesive or binder that becomes activated after application is provided for bonding side parts, wherein the application surface of the adhesive extends from at least one side fold line to at least an opposite fold line of the side part. It is extended continuously. The essence of the invention is the application of a continuous bead of adhesive or binder from one side fold line to the opposite fold line, the shape and thickness of the patch can be selected as required, a strip shape is preferred. .

Additionally, it is important that the application starts directly from within the side fold line and extends at least to the opposite fold line. This ensures that a continuous adhesive bond is created on the fold line of the paper bag, and the above-mentioned unfavorable channel occurrence can be effectively prevented. Later activation allows application earlier in the manufacturing process. In deactivated conditions, this eliminates the risk of contamination of each machine during subsequent manufacturing processes. Preferably, the activation takes effect directly before the final folding of the paper bag. There is therefore no need to leave the edge areas as well as the individual fold lines - as is the case when starch adhesives are used - and the adhesive or binder can be provided completely.

By side fold lines it is understood that there is this line of folds around which the side flaps are closed. In the case of cross and block bottom folds, folds are made at the ends along two side fold lines (also called side flap fold lines), whereby these fold lines reach the outside of the bag. End tucks are located in the outer regions of the side fold lines, at the cross base they are formed by outward facing edge folds, and at the bottom of the block by trapezoidal folds. These side portions are folded inwardly around the side fold line to adhere the side portions to the end folds and/or to each other by an adhesive or bonding agent.

Advantageously at least one continuous patch of adhesive or binder is provided in the area of each end of the side fold line, i.e. in the area of the two end tucks. In total, at least two, preferably four, continuous application surfaces of adhesive or binder are each provided on both the bottom and top parts. As long as integration of the valve for filling the paper bag is provided, the application of adhesive or binder in the area of the valve tube can be omitted.

Preferably, at least one adhesive or binder patch extends between the end regions of each side fold line, in particular transversely with respect to the bottom center line, which is located between each side fold line and holds the side parts together. It can be sealed by folding.

The patch of adhesive or bonding agent applied likewise extends beyond at least one side fold line, preferably directly up to the end tucks or beyond their posterior portion.

Also preferred is the application of multiple strip-like patches of adhesive and/or binder extending parallel to each other, preferably at least two strips extending parallel to each other at each end fold of the upper part and/or bottom ( It is provided in the area of end tuck).

Additionally, non-continuous patches or strips of adhesive or binder may also be provided, the areas falling above at least the lateral fold lines and/or the central fold line. The application of such an adhesive pattern, ideally with at least two strips of adhesive or binder running parallel, is particularly advantageous with non-continuous adhesives or binders if adhesives of different types are additionally used to glue the side parts. Adhesive patches with different types of adhesive can be arranged separately, overlapping or side by side.

Preferably, for a strong and stable adhesion the bottom and/or upper parts or their folds are additionally glued using independently applied adhesives, possibly by different types of adhesives, in particular based on starch-water mixtures. glued, wherein this adhesive is not applied to the areas of the folds, the side parts or the edge areas of the inner tucks, i.e. the application of the adhesive leaves these areas redundant. Particularly advantageous is the application of the adhesive and/or binder according to the invention in areas adjacent to the adhesive application. Ideally, there is alternating application of the adhesive and the adhesive and/or bonding agent used in the folding direction. For example, regions of the side parts that are located next to each other in the direction of the fold line are alternately glued to the inner fold using a starch adhesive or an adhesive or binder. Due to this process, the advantages of both types of adhesives can be realized in each area of adhesive bonding. Bonding paper with starch adhesives provides a particularly good, mechanically robust adhesive bond, since a good fiberization of the glued paper layer is achieved and the adhesive bond penetrates particularly deeply into the paper. On the other hand, the adhesive bond by means of the adhesive or binder used is not very strong, but provides a full-surface adhesive bond due to the continuous application transversely with respect to the floor center line, thereby acting disadvantageously. Channel formation is prevented and the channels that develop as a result of the starch adhesive adhesive bond are sealed.

The gluing agent is preferably wet gum or so-called envelope glue, which can be activated by the addition of a liquid or stream, in particular water or a stream. These properties can be deactivated by drying the adhesive, i.e. wet gum or sealing adhesive, after it has been applied to the paper bag, to avoid contamination of production machinery, for example during manufacturing. The adhesive may be activated immediately before or after folding. As mentioned above, wet gum refers to wet adhesive (wet gumming).

As a bonding agent, for example, a sealing composition, preferably a cold sealing composition, can be used, which is activated by pressure on a surface provided with the sealing composition and then acts as an adhesive. In these cases application of liquid or stream is not required. Equally possible is the use of hot melt adhesives, which are deactivated by cooling and later activated again by the supply of heat.

According to a preferred feature of the invention, the at least one film sealing the paper bag is capable of bonding the side parts and/or end tucks by means of an adhesive and/or binder and/or an applied adhesive. there is. The combination of such films, also referred to as inner linings, especially water- and dust-shielding films, is made to realize a particularly desirable sealing of paper bags. Therefore, the actual dust-shielding bag no longer becomes effective by folding the side parts, but only by applying the film. However, preferably the side parts are also folded and glued according to known methods for transport purposes.

The film forming the inner lining may preferably be formed of paper and/or coated paper and/or plastic material and/or metal thin film. The inner lining may partially or completely cover the applied patch of adhesive and/or bonding agent. In the case of partial covering, transitional areas of adhesive or bonding agent may act to adhere the side portions.

As well as the paper bag according to the invention, the invention relates to a method for producing the paper bag according to the invention with a folded bottom and/or top part. Before folding the bottom and/or top part, the adhesive and/or binder according to the invention is applied and/or printed on a paper roll or paper web to produce a paper bag. The application of the adhesive and/or binder is carried out so that the paper bag of the invention is obtained according to the process according to the invention or an advantageous application of the invention. Subsequently, the paper bag is folded and glued at the bottom simply by positioning the machine after applying a patch of adhesive and/or binder on the paper roll or paper web, wherein activation of the adhesive and/or binder used above causes only the folding or It is carried out immediately before or during the bonding process.

Additionally the water-starch mixture is preferably applied on a bottom laying machine, whereby adhesive areas are obtained with alternating patches of adhesive/binder and starch adhesive, in particular lateral folds or Alternating (repeating) adhesive areas in the direction of the floor center line are obtained.

According to a suitable embodiment of the method of the invention, the activation of the adhesive previously applied to the floor placement machine can be effected by the addition of water and/or a stream. When using water-starch mixtures for gluing side parts, it is convenient to simultaneously activate the adhesive applied in the floor laying machine by this addition of water. Additionally or alternatively, addition of the stream via a pressure nozzle can likewise be effected.

In an optional method step, at least one inner lining for an air-tight seal of the bag is adhered to the folded but still open bottom and/or top portion area by means of an applied adhesive and/or binder and/or starch-water mixture. It can be.

The application of the adhesive and/or binder on the paper web or paper roll is preferably effected via an impression cylinder which intermittently prints the desired patch shape, thereby obtaining the adhesive or binder pattern according to the invention. The application of these adhesives and/or binders is carried out by means of a flexographic printing machine.

The size and shape of the application patch and the application thickness of the adhesive and binder can be designed to vary, for example, depending on the materials and/or production equipment used and/or the intended application of the paper bag produced, i.e. the fill material required.

According to a suitable feature of the invention, the selected adhesive and/or binder is applied for creasing of fold lines or for any other treatment, for example by active or passive drying of the applied adhesive, followed by application of the method according to the invention. It is deactivated in the process, so that machine parts or tools subsequently used for corrugation or any other processing are not contaminated by the adhesive present in these areas. After such folding or other processing, i.e., when no more machine parts or tools are in contact with the fold line, the adhesive may become activated. According to another suitable feature of the invention, hot melt adhesives can also be applied as adhesives, and these adhesives can be activated by applying heat. Particularly preferably the hot melt adhesive is applied on the paper bag under high temperature or hot conditions and is deactivated initially after application by cooling. Activation of the hot melt adhesive is then effected by supplying heat to close or block the bottom or top portion.

If a sealing composition, particularly preferably a cool sealing composition, is used, the adhesive effect can be activated by compressing the patch covered with the cool sealing composition. For this purpose the cold sealing composition must be applied between the side fold lines as well as over the corresponding patches between the fold lines and on the area of the side part that is under pressure.

Additional advantages and properties of the invention will be described in detail below with reference to exemplary embodiments presented in the drawings.

The paper bag according to the present invention ensures that the folded portion is completely sealed while preventing the creation of channels during the application of the adhesive.

Figure 1 shows the overall plan view of a paper bag according to the invention with a bottom and a top part.
Figure 2 shows a plan view of the open bottom of a paper bag according to the prior art.
Figure 3 shows a plan view of the open bottom of a paper bag according to the invention.
Figure 4 shows a perspective view of a cross-section of a paper web for manufacturing a paper bag according to the invention.
Figure 5 shows another plan view of an open-bottomed paper bag according to the present invention.
Figure 6 shows a plan view of the sealed bottom of a paper bag according to the invention.

Below, the present invention will be described in detail with reference to the embodiments shown in the attached drawings, but the examples are for a clear understanding of the present invention and the present invention is not limited thereto. In the description below, components having the same reference numerals in different drawings have similar functions, so unless necessary for understanding the invention, the description will not be repeated, and well-known components will be briefly described or omitted, but the present invention It should not be understood as being excluded from the embodiments.

1 shows a paper bag according to the invention with a cross bottom 2 and an upper part 3, wherein ) is folded on the front side (9) of the paper bag (10). What is not visible in the drawing is the back of the bag (10), and the back is located below the front (9). A valve tube (50) is inserted into the upper part (3) to fill the paper bag (10).

Paper bags may contain two or more layers of paper or material. The specific design of the paper bag 10, i.e. the number of paper layers used or the number of material layers, is not relevant to the practice of the invention and therefore it will not be described in detail below. In the upper part a valve 50, known per se, can be provided for filling the bag.

To illustrate the advantages of the invention, an initially open, partially folded bottom portion 2 of a known paper bag 1 is shown in FIG. 2 . A detailed view of the bag bottom (2) of a known paper bag (1) with cross bottoms is shown. However, in Figure 2 the cross bottom (2) is not closed, but the side flaps (5) are open and the inner corner tucks (6) are visible. To fold the cross floor, both side flaps (5) are folded inward in the direction of the arrow (7). That is, it is folded along each side flap fold line 4 where a bottom creasing is provided.

In order to glue the cross bottom, i.e. the two side flaps (5), the glue (8) of the starch-water mixture is applied flat to an area on the corresponding surface, folding the upper side flaps into the corner inwards (6) and The lower side flaps (5) are glued to the surface of the side flaps (5) that were previously folded inward. Additionally in Figure 2, in the areas of the upper and lower side flap fold lines 5, no adhesive 8 is left, thereby leaving these areas adhesive-free. The same method is applied to the corner inner folds 6 and the edge areas of the side flaps 5, with the outer edges remaining entirely adhesive-free.

This absence of adhesive means that it must not be placed on production tools that require adhesive during the production process, especially in the production of bottom creases along the fold line (4), or on machine parts located underneath during the production process where adhesive is applied to the edge area. It has a technical background that ensures that no contamination occurs. However, the absence of adhesive along the fold line 4 and in the edge area creates unfavorable air-permeable and dust-permeable channels, which makes it difficult to fill the material from the inside of the bag at the exit 21 of the bottom center line 4”. ), and can reach the outside via the bag edge 20 shown in Figure 6. Increasing the channel results in compression of the paper when sealing the bottom, resulting in additional undulation of the paper and wrinkling and displacement in the area of the adjacent edges of the bottom center line (4”). It is due to the fact that it occurs. Since the starch adhesive 8 is not completely injected and does not reach the folded edges, wrinkles, folds and edges are also not completely bonded using the starch adhesive 8.

The solution according to the invention is illustrated in Figure 3. The figure likewise shows the open and partially folded cross bottoms 2 of the paper bag 10 according to the invention. The features of the cross floor 2 that are identical in relation to the prior art are given identical reference signs. The wet gum (11) according to the invention is applied continuously between the two side fold lines (4) of the side part (5). Distinctive points, indentations (4'), especially in the area of the side fold lines (4) and possible paper folds, especially in the area of the bottom center (4"), are air-tight. It can be sealed (air-tight), and as a result, discharge of the filling material is prevented using the sealed paper bag (10).

In the embodiment according to FIG. 3 , additional wet gum 11 is applied on the inner corner tucks 6 of the floor 2 with a special adhesive pattern. In particular, two parallel continuous adhesive strips 11' and a discontinuous adhesive strip 11" extend from one side fold line 4 to the opposite side fold line 4. At their ends adhesive strips (11', 11") are connected to each other over the entire adhesive surface (11"').

The preferred arrangement of the adhesive surfaces 11 makes it possible to apply the activatable adhesive 11 and the known starch adhesive 8 alternately in the direction of the center line 4", thereby allowing advantageous use of both adhesives. Let it be made with the positive properties of (8, 11). Starch adhesive 8 is typically applied using the pattern according to FIG. 2 .

Wet gum 11 as an adhesive is shown as an exemplary embodiment, but alternatively the use of sealing compositions, especially cold sealing compositions or the use of hot melt adhesives may be considered. .

A manufacturing method for the production of a paper bag 10 according to the invention with folding lines 4, 4″ sealed in a dust-shielded manner is described below. Adhesive 11 in the form of wet gum or cold sealing composition is applied intermittently (discontinuously) in a sheet metal printing machine via an imprint cylinder on a paper roll or paper web 100 as shown in FIG. 4 . Adhesive 11 is applied in areas of the paper web 100, whereby in the process below the bottom fold the adhesive provides an adhesive pattern 11 as shown in Figure 3.

The size and shape of the application patch and the application thickness of the activatable adhesive 11 or the cold sealing composition depend, for example, on the material used for the manufacture of the paper bag 10 or on the manufacturing process used or on the paper bag produced. (10) can be variably designed depending on the selected filling material.

In the next step the paper webs 100 are folded together overlapping in the longitudinal direction and glued in so-called tubers, thereby forming a tube, which is then cut to the appropriate length. The tube parts, pre-printed with adhesive 11 or cold sealing composition, are then transferred to a floor placement machine in the manufacturing process. In a bottom placing machine, the bottom 2 of the bag is folded as shown in Figure 3 and a known adhesive mixture 8 for gluing cross bottoms 2 is applied to the corner inward folds 6 as shown in Figure 5. It is applied on top of the side part (5). The adhesive (8) used is based on a starch-water mixture, so that during the application process the same is excluded from the area of the side flap fold lines (4) and from the area of the side flaps (5) and the corner inner folds (6). Be careful. Similarly, on the floor placement machine, floor folds are made along the side flap fold lines (4).

The moistening necessary for the activation of the adhesive 11 is effected by means of the applied starch-water mixture 8. This is done due to the fact that the adhesive 11 is activated by the capillary effect of the paper. The water contained in the starch adhesive 8 smears on the paper and spreads up to the adhesive points 11, thereby partially dissolving the same and making it sticky by way of sealing adhesion.

Optionally, moistening of the adhesive 11 can be supplemented by steam through a suitable nozzle.

The folded cross bottom (2) of the paper bag (10) according to the invention is now well sealed in the area of the side flap fold lines (4), the bottom center channel (4") and the edge area (4'), whereby In particular, in the area of the bag edge 20 shown in Figure 6, the filling material can no longer be discharged to the outside. This makes the bag 10 significantly more dust-proof, thereby preventing contamination of the bag 10 being filled with pellets, as well as contamination of the customer's filling facility.

The upper part (3) can be designed in a similar way to the bottom (2).

Preferably before folding the side parts 5 a so-called inner lining can additionally be applied, which ensures that the bottom part 2 of the paper bag 10 is sealed in an air-tight manner. Such an inner lining constitutes, for example, a plastic film that completely covers the adhesive surface of the adhesive 11 or, alternatively, is only partially glued onto a certain surface of the adhesive 11 . In any case, the adhesive is effective in such a way that the opening in the bottom part 2 is completely air- and dust-sealed by the film. The side parts 5 do not contribute to the dust-proof sealing of the paper bag, but only contribute to the optical design of the paper bag 10 for transport purposes.

If an inner lining is used, gum 11 can also be excluded in principle. When using an inner lining, a special procedure may be in which a starch frame is applied to the inner lining, which is then glued onto the open bottom (2). The starch is then applied directly and completely onto the base 2, so no gum is required. Various modifications can be designed such that the gum 11 for gluing the floor is only partially covered by the inner lining. The uncovered portion is then glued to seal the bottom (2).

Although the present invention has been described in detail above with reference to the presented embodiments, those skilled in the art will be able to make various variations and modifications without departing from the technical spirit of the present invention by referring to the presented embodiments. . The present invention is not limited by such variations and modifications, but is limited by the claims appended below.

1: Paper bag 2: Bottom
3: Upper part 4: Fold line
4': Floor center line 4": Floor center line
5: Side flap 6: Inward corner fold
7: Arrow direction 8: Starch adhesive
9: Front 10: Paper bag
11: wet gum, adhesive 11': parallel continuous adhesive strip
11": Discontinuous adhesive strip 11"': Entire adhesive surface
20: back edge 21: outlet
50: valve 100: paper web

Claims (17)

A paper bag having a bottom and an upper portion facing the bottom, the paper bag comprising:
The bottom or top part of the paper bag is folded and glued with the side parts closed along a fold line located on the side of the bottom or top, forming a cross-shaped or block-shaped bottom,
For adhesion of the side parts, several strip-shaped adhesive or binder patches are provided in the folds of the two end parts located on the sides, activated after application and extending parallel to each other, the other being on one side of the fold line of the side parts. Provided continuously to the side,
The adhesive or binder is provided in the form of at least one discontinuous patch or strip-shaped patch, wherein the patch spans at least one of a fold line on the side portion and a fold line formed at the center of the bottom. Paper bag. In claim 1,
and wherein at least one of said patches of adhesive or binder extends beyond at least one of said side fold lines. In claim 2,
wherein the patch of adhesive or binder extending beyond at least one side fold line extends directly beyond an edge of the end fold or an edge of the end fold. In claim 1,
A paper bag, wherein the adhesive is a wet gumming that is activated by adding liquid or vapor, and the binder is a sealing composition. In claim 4,
The liquid is water, or
A paper bag, characterized in that the sealing composition is a cooling sealing composition. In claim 1,
The folding of the bottom or upper portion is,
Paper bag, characterized in that it is additionally bonded by an independently applied adhesive. In claim 6,
A paper bag, characterized in that the independently applied adhesive consists mainly of a starch-water mixture. In claim 6,
The independently applied adhesive and the patch of the adhesive or binder,
A paper bag characterized in that it is applied alternately along the folding direction. In claim 1,
In at least one of the side portion and the end fold,
A paper bag, characterized in that at least one film for sealing the paper bag is attached through an adhesive or binder. In claim 9,
A paper bag, characterized in that the film completely or partially covers the applied patch of adhesive or binder. In the method of manufacturing a paper bag with a folded bottom or top portion according to claim 1,
For the manufacture of paper bags, an activatable adhesive or binder is at least applied or printed on a paper roll or paper web,
A method of manufacturing a paper bag, characterized in that the bottom or top portion is then folded in a bottom placing machine. In claim 11,
A starch-water mixture is provided to the floor placing machine,
A method of manufacturing a paper bag, wherein the application of the adhesive or binder and the application of starch are alternately performed along a fold line of the side portion and a fold line formed at the center of the bottom. In claim 11,
The adhesive coated with
A method of manufacturing a paper bag, characterized in that the floor placement machine is activated by adding at least one of water or steam. In claim 12,
The adhesive coated with
A method of manufacturing a paper bag, characterized in that it is activated by applying a starch-water mixture. In claim 11,
Film to keep paper bags airtight,
Through at least one of an adhesive or binder or a starch-water mixture,
A method of manufacturing a paper bag, characterized in that it is glued to the bottom or top portion of a folded or open paper bag. In claim 11,
The adhesive or binder is attached to the paper roll or the paper web at predetermined intervals through an impression cylinder. In claim 15,
A method of manufacturing a paper bag, characterized in that the adhered film completely or partially covers the applied patch of adhesive or binder.